| 摘要 |
<p>PURPOSE:To obtain a slicing means having a large margin in the width direction by obtaining a midpoint of black and white levels and by slicing an output signal of a mark sensor based on the midpoint level. CONSTITUTION:An output signal from a mark sensor is given for an input terminal 6, and one peak value of the signal equivalent to a white level is extracted by a white level holding circuit 1 and held. A differential amplifier 2 inverts and amplifies an input signal using a white level as reference. Then the other peak value equivalent to a black level is extracted in a black level holding circuit 3 and held. A signal component held between black and white levels is outputted to the circuit 3, divided into 1/2 by a voltage divider 5, and a central level is extracted. A comparator 4 slices an output from the amplifier 2, using a voltage at a central level as a slicing level, generates a pulse signal and outputs it to an output terminal 7.</p> |
